This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We hypothesize that, with the inclusion of mucosal chemokines with the DNA plasmid immunizations, a stronger mucosal immune response will be induced and that this response will correspond to increased efficacy against SIV challenge. Experiment 1: Twenty female Indian origin Rhesus macaques (Macaca mulatta) were previously immunized five times with DNA and various chemokines. In 2010, all 20 immunized animals plus 6 unimmunized animals were intravaginally challenged with SIVsmE660 twice a week for two weeks. Blood samples and mucosal lavages (including washes of the duodenum, lung and vagina) were collected at specified times after challenge and shipped to the University of Pennsylvania for analysis of immune responses. Blood samples and mucosal biopsies (including duodenum and vagina) were also collected after challenge and analyzed at the TNPRC to monitor viral infection and immune responses. Results of the challenge are as follows: 5 of 6 unimmunized control animals, 3 of 5 animals treated with DNA only, 4 of 5 animals treated with DNA+cTack, 2 of 5 animals treated with DNA+Teck and 4 of 5 animals treated with DNA+Meck became infected. However, the peak plasma virus loads of the DNA+Meck animals were greatly reduced compared to the unimmunized controls. All animals (n=18) that became infected were euthanized in 2010;all uninfected animals (n=8) will be used in the next experiment. Experiment 2: Based on the data obtained from the challenge results in Experiment 1, 16 new Rhesus macaques and the 8 uninfected macaques from Experiment 1 are being used in this experiment. Animals will be vaccinated five times with either SIV DNA + Teck, Flu DNA +/- Meck or C.Diff DNA +/- Meck. After the last vaccination, all animals will be challenged with SIVsmE660. Blood and mucosal samples will be collected to monitor viral infection and immune response.